I use Promix for herbs and veggies in my containers for compact tomatoes.

BER is caused by uneven watering. It is not due to a lack of calcium, but because the plant is unable to take-up calcium because of the stress. People add calcium and think it has helped, but really the problem has gone away. It is usually the plum-type tomatoes that are affected by BER, and usually just the first few fruits. If you can keep the watering consistent and if it doesn't rain too much, everything should be fine.

Positive attributes of potting soil are its free-draining quality and its lack of pathogens (which is most important for seed germination and seedling survival). But, potting soil may contain little nutrient value on its own. It is most often a combination of peat moss, coconut fiber (coir), and composted tree waste from sawmills, along with perlite and vermiculite. Sand and soil are rarely used because they are heavy. The terms natural or organic mean nothing. There is no federal standard for potting soil as there is for organic food products. The term compost can refer to sewage sludge.

You can add calcium and other rock dust to potting soil, but these take time to be utilized. Liquid fertilizers give you quick results. Look for those that include more than NPK nutrients, such as GS Plant Foods Organic Liquid Kelp, or Fox Farm Grow Big and Big Bloom formulas, or Plant Magic All Purpose Organic Plant Food.

Yes, uneven watering, and rapid growth early in the season. I never really found a good way to manage a little BER, even though it dissipates later in the season. I'm not offering a cure, nor do I have any affiliation, but, when I started using Texas Tomato Food, BER has disappeared. They do advertise their food stops BER, but I'm always skeptical of claims like that. I bought some because it is the best on the market to feed plants, and also noticed that I haven't had any BER since. Coincidence? Not sure, but I'll take it.

You might find this article by Dr Carolyn Male helpful.

Article on Calcium/BER

or this one is less technical and shorter too.

Garden Myths

I have to admit, I'm a bit frustrated. I'm trying to get a better idea of what people are doing about calcium with their potted plants. Instead I hear BER "is not due to a lack of calcium" and garden myths.

But I want to keep an open mind here. I could be wrong, I just need some assistance helping me to understand it.

If the plant is in the ground and not in a pot--I agree with the above statements. The plant probably isn't fighting a lack of calcium in the soil. We're in agreement.

But the question is for potted plants. In my case, I'm growing in 5 gallon buckets. At this point many of them are root bound. They are pulling everything out of the soil and will soon produce fruit, which will pull calcium out of the soil constantly. Does hardware store soil in a bucket have enough calcium for a whole season of heavy fruiting plants? Maybe the water from my hose is enough to replenish the calcium needs? I wouldn't rule it out but a quick Google check says 40-80 ppm, so we're looking around 0.00006%.

But I do find edweather's response helpful. He mentions Texas Tomato Food. I looked it up and it specifically states that it has calcium built in, but I couldn't find out exactly how much. To edweather, I'm curious how often you use it and how much.

The TTF label says 2.5% Calcium. I use it almost every day. I soak my containers first. I then add about 3 tablespoons to a typical watering can. Then I pour a little on top of the soil so it leaches in. One watering can will spread out over about 8 containers. Sometimes I skip a day, or supplement MG liquid. The main thing is to feed weakly but often.

I want to thank gardengal48 and edweather for the posts—this really helps me out and changes how I think.

• I’ve never grown a dwarf tomato—I want to try that out for sure.
• “Weakly, weekly” I’ll remember this going forward
• With regards to Osmocote Plus, I’ve never mixed fertilizer with the soil before potting. Now I want to experiment with this.
• Edweather—you mention 2.5% calcium. I actually have multiple fertilizers with 0% calcium. I won’t be using that much anymore.

What I take from this is that if you water properly and fertilize regularly, and correctly, and use fertilizer with calcium mixed in, you should very likely be in good shape.

To you both, I really appreciate your help. It has changed my strategy and I’m sure will greatly help moving forward.